CN111190075B - Distribution line fault positioning method based on pulse signal injection - Google Patents

Abstract

The invention provides a distribution line fault location method and system based on pulse signal injection. The method includes: a plurality of partial discharge detection sensors installed in sequence on the distribution line monitor the first pulse signal sent from the fault point; The relative phases of the first pulse signals monitored by all partial discharge detection sensors relative to the power frequency voltage signal on the distribution line; the first monitoring position where the corresponding partial discharge detection sensors are located when the minimum relative phase is obtained, and the first monitoring Monitoring positions adjacent to both sides of the position; obtain three relative phases of the first pulse signal corresponding to the above three monitoring positions; analyze the three relative phases, and calculate and obtain the first monitoring position and the second monitoring position and the third monitoring position respectively. Distance information between positions; according to the distance information, determine the section where the fault point is located. The present application can quickly locate the section where the fault of the power distribution line is located, and has the characteristics of high efficiency, intelligence, convenience, and the like.

Description

A fault location method for distribution lines based on pulse signal injection

technical field

The invention belongs to the technical field of power grid fault detection and location, and in particular relates to a distribution line fault location method based on pulse signal injection.

Background technique

The distribution network is the link between supply and demand that connects the transmission network and power users. The distribution network belongs to the end of the power system and is directly oriented to users. It is an important public infrastructure that serves people's livelihood. The length of distribution network lines accounts for about 90% of the length of power grid lines at all levels. It has the characteristics of many changes in line structure and complex fault conditions. Statistics show that more than 80% of power outage accidents are caused by distribution network faults. It will seriously affect the safe and stable operation of the power grid. In severe cases, it will lead to large-scale power outages in key areas, causing huge losses to the national economy and people's lives, and even endangering personal safety.

The most common fault in distribution line is ground fault, among which single-phase ground fault has the highest probability. Precise location of distribution network faults is a key technology to reduce outage time and speed up power supply recovery. The conventional single-phase-to-ground fault location method uses the overvoltage signal, which has low accuracy, unsatisfactory error control, and low fault finding efficiency, requiring a lot of manpower and material resources. In addition, there are many changes in the line structure of the distribution network. When latent faults such as insulation faults of equipment and distribution lines in the system occur, there is also the problem of difficulty in fault location.

Therefore, when a single-phase ground fault and a latent fault occur in the distribution network, how to quickly locate the fault and improve the accuracy of the fault location is a technical problem to be solved by those skilled in the art.

SUMMARY OF THE INVENTION

The invention proposes a distribution line fault location method based on pulse signal injection, which solves the technical problems of rapid fault location and improved fault location accuracy when single-phase grounding faults and latent faults occur in the distribution network.

In order to solve the above-mentioned technical problems, the technical scheme adopted in the present invention is:

Provided is a distribution line fault location method based on pulse signal injection, the method is as follows:

Multiple partial discharge detection sensors installed in sequence on the distribution line monitor the first pulse signal sent from the fault point;

Analyzing and obtaining the relative phases of the first pulse signals monitored by all the partial discharge detection sensors with respect to the power frequency voltage signal on the distribution line;

obtaining the first monitoring position where the partial discharge detection sensor corresponds to when the minimum value of the relative phase is obtained, and the second monitoring position and the third monitoring position adjacent to the first monitoring position;

acquiring a first relative phase, a second relative phase and a third relative phase of the first pulse signal corresponding to the first monitoring position, the second monitoring position and the third monitoring position;

Analyzing the first relative phase, the second relative phase and the third relative phase, and calculating the first distance between the first monitoring position and the second monitoring position, the first monitoring position a second distance from the third monitoring location;

According to the first distance and the second distance, determine the section where the fault point is located;

If the first distance is equal to the length of the section between the first monitoring position and the second monitoring position stored by the system, and the second distance is not equal to the first monitoring position stored by the system and the second monitoring position the length of the section between the third monitoring positions, the fault is located between the first monitoring position and the third monitoring position;

If the first distance is not equal to the length value of the section between the first monitoring position and the second monitoring position stored by the system, and the second distance is equal to the first monitoring position stored by the system and the second monitoring position If the length value of the section between the third monitoring positions, the fault is located between the first monitoring position and the second monitoring position.

Preferably, the length of the section between the first monitoring position and the second monitoring position stored by the system, the length of the section between the first monitoring position and the third monitoring position stored by the system , which is derived from the data obtained and stored from the online ranging of the distribution line, where the online ranging includes:

selecting any monitoring position of the partial discharge detection sensor on the distribution line, and injecting a second pulse signal into the monitoring position;

All the partial discharge detection sensors are monitored to obtain the second pulse signal;

Analyzing all the second pulse signals to obtain the relative phases of the second pulse signals relative to the power frequency voltage signal at all the monitoring positions;

calculating the relative phase difference of the second pulse signal from one of the monitoring positions to the adjacent monitoring positions;

According to the relative phase difference, the distance between the monitoring position and the adjacent monitoring position is obtained and stored, and the distance is:

Wherein, V is the propagation speed of the pulse signal in the power distribution line, and V=3*10 ⁸ m/s (speed of light).

Further, the phase where the maximum amplitude intensity of the first pulse signal is located is the faulty phase.

Further, the first distance is:

Among them, V is the propagation speed of the pulse signal in the line, V=3*10 ⁸ m/s (speed of light).

Further, the second distance is:

Among them, V is the propagation speed of the pulse signal in the line, V=3*10 ⁸ m/s (speed of light).

According to the second part provided by the embodiments of the present invention, a distribution line fault location system based on pulse signal injection, the system includes a signal generating device, a plurality of partial discharge detection sensors, and a control center;

The signal generating device is connected to the calibration interface of the partial discharge detection sensor, and is used for injecting a second pulse signal into the distribution line to be tested, wherein the first pulse signal is generated when the distribution line fails;

The partial discharge detection sensor is installed in sequence along the distribution line segment, one end is connected to one end of the coupling capacitor, and the other end is grounded, and is used to collect the power frequency voltage signal and the first pulse signal in the distribution line. and the second pulse signal, and communicate and transmit the power frequency voltage signal, the first pulse signal and the second pulse signal to the control center;

The control center is used to receive and analyze the power frequency voltage signal, the first pulse signal and the second pulse signal, and calculate and obtain the distance information of the monitoring positions of the two adjacent partial discharge detection sensors and Fault location information, storing the distance information and the fault location information.

Further, the partial discharge detection sensor includes:

a signal acquisition module for acquiring and recording the power frequency voltage signal, the first pulse signal and the second pulse signal;

The first communication module is used for transmitting the power frequency voltage signal, the first pulse signal and the second pulse signal to the control center.

Further, the control center includes:

a second communication module, configured to transmit the power frequency voltage signal, the first pulse signal and the second pulse signal with the partial discharge detection sensor;

A data analysis module is used to analyze and process the power frequency voltage signal, the first pulse signal and the second pulse signal, and obtain the voltage amplitude and phase of the distribution line and the first pulse signal, the the relative phase of the second pulse signal with respect to the power frequency voltage signal;

a fault detection module, used for judging whether the power distribution line is faulty according to the second pulse signal;

A fault location module, configured to determine the section of the distribution line where the fault point is located according to the relative phase, and calculate the distance between the fault point and the two adjacent installation positions of the partial discharge detection sensors;

The human-computer interaction module is used to display the operation status of the distribution line for users to query the information of the distribution line.

Based on the above embodiments, it can be seen that the embodiment of the present invention provides a distribution line fault location method based on pulse signal injection. The method first monitors the number of partial discharge detection sensors that are sequentially installed on the distribution line. The amplitude strength of a pulse signal; the first monitoring position corresponding to the minimum value of the amplitude strength of the first pulse signal is obtained; further obtain the first monitoring position and the second monitoring position and the third monitoring position adjacent to the first monitoring position The first amplitude intensity, the second amplitude intensity and the third amplitude intensity of the corresponding first pulse signal at The first distance between the position and the second monitoring position, the second distance between the first monitoring position and the third monitoring position; according to the first distance and the second distance, determine the section where the fault point is located; if, the first distance If it is equal to the length of the section between the stored first monitoring position and the second monitoring position, and the second distance is not equal to the length of the section between the stored first monitoring position and the third monitoring position, the fault is located between the first monitoring position and the third monitoring position. Between the third monitoring positions; if the first distance is not equal to the stored length value of the section between the first monitoring position and the second monitoring position, and the second distance is equal to the stored first monitoring position and the third monitoring position If the length value of the segment is equal, the fault is located between the first monitoring position and the second monitoring position; the method provided in this embodiment effectively realizes the judgment of the segment where the fault point is located. The pulse signal generated when the fault occurs is easy to collect, so this method has the characteristics of fast response, and the fault location is based on the voltage phase when the pulse signal is detected, and does not involve steps such as precise time synchronization, which solves the difficulty in the time synchronization process. It avoids the problem of errors, greatly reduces the burden of operation and maintenance personnel, shortens the troubleshooting time, and effectively improves the power supply reliability and intelligence level of the transmission line.

Description of drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description serve to explain the principles of the invention.

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. In other words, on the premise of no creative labor, other drawings can also be obtained from these drawings.

FIG. 1 is a schematic structural diagram of a distribution line fault location system according to an embodiment of the present invention;

Figures 2(a) and 2(b) are schematic diagrams of a distribution line fault location method based on pulse signal injection provided by an embodiment of the present invention, wherein Figure 2(a) is a schematic diagram of the location of the fault point, and Figure 2( b) is a schematic diagram of the relative phase;

FIG. 3 is a flowchart of a method for locating a distribution line fault based on pulse signal injection according to an embodiment of the present invention.

Detailed ways

In order to make those skilled in the art better understand the technical solutions in the present application, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the scope of protection of the present application.

FIG. 1 is a schematic structural diagram of a distribution line fault location system provided by an embodiment of the present invention. As shown in FIG. 1 , the system includes a signal generating device 3 , a plurality of partial discharge detection sensors 4 , a control center 5 and a plurality of Coupling capacitor 2. The partial discharge detection sensor 4 includes a signal acquisition module and a first communication module, and the control center 5 includes a second communication module, a data analysis module, a fault detection module, a fault location module and a human-computer interaction module.

Specifically, the signal generating device 3 is connected to the calibration interface of the partial discharge detection sensor 4, and is used for injecting a second pulse signal into the distribution line 1 to be tested, wherein the distribution line 1 has a potential such as a single-phase ground fault or an insulation fault. When the fault occurs, the first pulse signal is generated. Preferably, the signal generating device 3 is a common pulse signal generating device in the market, and the generated first pulse signal is a square wave pulse signal.

According to the location, natural environment, working conditions and other specific conditions of the distribution line 1, the partial discharge detection sensor 4 is installed in sequence along the bus bar of the distribution line. The distribution line section can be segmented for a short distance, that is, the partial discharge detection sensors 4 are installed relatively densely. When the partial discharge detection sensor 4 is installed on the bus of the distribution line 1, a coupling capacitor 2 needs to be installed between the bus of the distribution line 1 and the partial discharge detection sensor 4. The coupling capacitor 2 has the function of blocking high voltage and coupling signals. The configuration of the coupling capacitor 2 can realize that the signal generating device 3 directly injects the second pulse signal when the power distribution line 1 is energized, thereby realizing online ranging. The other end of the partial discharge detection sensor 4 is grounded to prevent high-voltage electric shock. The partial discharge detection sensor 4 is used to collect the power frequency voltage signal in the distribution line 1, the second pulse signal injected by the signal generating device 3 and the first pulse signal generated when the power distribution line 1 fails, and convert the power frequency voltage signal. , the first pulse signal and the second pulse signal are communicated and transmitted to the control center 5 . Further, the partial discharge detection sensor 4 includes a signal acquisition module and a first communication module, wherein the signal acquisition module is used to collect and record the power frequency voltage signal, the first pulse signal and the second pulse signal; the first communication module is used to The power frequency voltage signal, the first pulse signal and the second pulse signal are transmitted to the control center 5 .

The control center 5 is used to receive and analyze the power frequency voltage signal, the first pulse signal and the second pulse signal, calculate and obtain the distance information and fault location information of the installation positions of the two adjacent partial discharge detection sensors 4, and store the distance information and Fault location information. Further, the control center 5 includes a second communication module, a data analysis module, a fault detection module, a fault location module and a human-computer interaction module. Wherein, the second communication module is used to transmit the power frequency voltage signal, the first pulse signal and the second pulse signal with the partial discharge detection sensor 4 . The data analysis module performs digital analysis on the waveform of the power frequency voltage signal to obtain a digital signal, and then obtains the voltage amplitude and phase of the distribution line corresponding to the power frequency voltage signal; the data analysis module analyzes the first pulse signal and the second pulse signal, Through the comparison and analysis of the pulse signal and the power frequency voltage signal, the relative phases of the first pulse signal and the second pulse signal with respect to the power frequency voltage signal are obtained. The fault detection module is used to judge whether the power distribution line is faulty according to the second pulse signal. Specifically, when the second communication module receives the second pulse signal and transmits it to the fault detection module, the fault detection module receives the second pulse signal. The pulse signal can be judged that the distribution line 1 is faulty, and the line with the largest amplitude of the first pulse signal is the faulty phase. The fault location module is used for judging the section of the distribution line 1 where the fault point is located according to the relative phase, and calculating the distance between the fault point and the installation positions of the two adjacent partial discharge detection sensors 4 . The human-computer interaction module is used to display the operation status of the distribution line 1 and allow users to query the information of the distribution line 1.

Based on the above implementation principle, the fault location method provided in this embodiment will be described in detail below with reference to the accompanying drawings. FIG. 2 is a schematic diagram of a method for locating faults in distribution lines based on pulse signal injection provided by an embodiment of the present invention, in which FIG. (a) is a schematic diagram of the location of the fault point, and FIG. A flowchart of a method for locating a distribution line fault provided in an embodiment of the invention. As shown in Figure 3, the positioning method includes the following steps:

S101 Multiple partial discharge detection sensors installed in sequence on the distribution line monitor the first pulse signal sent out at the fault point.

When a latent fault such as a single-phase ground fault or an insulation fault occurs in the distribution line, a pulse signal will be generated at the fault point. In order to distinguish the signal sent by the signal generator, it is named the first pulse signal. All partial discharge detection sensors installed on the distribution line monitor the first pulse signal sent out at the fault point, and send the detected first pulse signal to the control center. The fault detection module of the control center analyzes the first pulse signal, and determines that the phase where the maximum amplitude intensity of the first pulse signal is located is the fault phase.

S102 analyzes and obtains the relative phase of the first pulse signal monitored by all partial discharge detection sensors with respect to the power frequency voltage signal on the distribution line.

When a single-phase grounding fault or insulation fault occurs in the distribution line, the partial discharge detection sensors installed in different positions monitor the first pulse signal. Since the installation position of the partial discharge detection sensor is different relative to the fault point, the relative phase of the first pulse signal monitored by each partial discharge detection sensor installed on the faulty line is different from the power frequency voltage signal of the distribution line, and further The second pulse signal received by the control center has different relative phases, and the different relative phases are in one-to-one correspondence with the monitoring positions of the partial discharge detection sensors. The data analysis module of the control center analyzes the obtained first pulse signals, obtains the relative phases of all first pulse signals relative to the power frequency voltage signal on the distribution line, and the monitoring position of the partial discharge detection sensor corresponding to each relative phase.

S103 , when the minimum value of the relative phase is obtained, the corresponding first monitoring position where the partial discharge detection sensor is located, and the second monitoring position and the third monitoring position adjacent to the first monitoring position.

S104 acquires the first relative phase, the second relative phase and the third relative phase of the first pulse signal corresponding to the first monitoring position, the second monitoring position and the third monitoring position.

According to the definition and characteristics of the phase, the relative phase of the second pulse signal monitored by the partial discharge detection sensor at the position closest to the fault point is the smallest. According to this characteristic, the rough position of the fault point can be preliminarily determined. Therefore, the fault location module of the control center, based on all the relative phases of the first pulse signal obtained by the analysis in step S102 and the monitoring positions of the corresponding partial discharge detection sensors, filters out the first monitoring of the partial discharge detection sensor corresponding to the smallest relative phase. position, and the second monitoring position and the third monitoring position adjacent to the first monitoring position, and simultaneously obtain the first relative phase, the first relative phase, the first pulse signal corresponding to the first monitoring position, the second monitoring position and the third monitoring position. Two relative phases and a third relative phase.

S105 analyzes the first relative phase, the second relative phase and the third relative phase, and calculates the first distance between the first monitoring position and the second monitoring position, and the second distance between the first monitoring position and the third monitoring position .

The phase represents the position information of the first pulse signal in the cycle in which it is located at a specific moment. Therefore, the corresponding position information can be obtained according to the phase information, and then the distance information can be obtained. Specifically, the fault location system of the control center analyzes the first relative phase, the second relative phase and the third relative phase, and calculates the first distance between the first monitoring position and the second monitoring position, the first monitoring position and the third relative phase. A second distance between the monitoring locations is monitored.

The first distance is:

The second distance is:

Among them, V is the propagation speed of the pulse signal in the line, V=3*10 ⁸ m/s (speed of light).

S106, according to the first distance and the second distance, determine the section where the fault point is located.

S107 If the first distance is equal to the length of the section between the first monitoring position and the second monitoring position stored in the system, and the second distance is not equal to the length of the section between the first monitoring position and the third monitoring position stored in the system, The fault is then located between the first monitoring position and the third monitoring position.

S108 If the first distance is not equal to the length value of the section between the first monitoring position and the second monitoring position stored by the system, and the second distance is equal to the length of the section between the first monitoring position and the third monitoring position stored by the system value, the fault is located between the first monitoring position and the second monitoring position.

Preferably, the length of the section between the first monitoring position and the second monitoring position stored by the system is derived from the data obtained and stored by online ranging of the distribution line, and the difference between the first monitoring position and the third monitoring position stored by the system. On-line ranging includes: selecting the monitoring position where any partial discharge detection sensor on the distribution line is located, and using the signal generating device to inject the second pulse signal into the monitoring position; all partial discharges on the distribution line Detecting the sensor, monitoring to obtain the second pulse signal, and sending it to the control center; the data analysis module of the control center analyzes all the second pulse signals obtained, and obtains the relative phase of the second pulse signal relative to the power frequency voltage signal at all monitoring positions; The fault location module of the control center calculates the relative phase difference of the second pulse signal from one monitoring position to the adjacent monitoring position, and then obtains and stores the distance between the monitoring position and the adjacent monitoring position according to the relative phase difference, and the distance is:

Among them, V is the propagation speed of the pulse signal in the distribution line, V=3*10 ⁸ m/s (speed of light).

The embodiments in this specification are described in a progressive manner. Other embodiments of the invention will readily suggest themselves to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses or adaptations of the invention which follow the general principles of the invention and which include common knowledge or conventional techniques in the art to which the invention is not invented . The specification and examples are to be regarded as exemplary only, with the true scope and spirit of the invention being indicated by the appended claims.

It should be noted that, unless otherwise specified and limited, the terms "connected" and "connected" should be understood in a broad sense, for example, it may be a mechanical connection or an electrical connection, or the internal communication between two elements, or a direct connection, It can also be indirectly connected through an intermediate medium, and those of ordinary skill in the related art can understand the specific meanings of the above terms according to specific situations. The terms "comprising", "comprising" or any other variation thereof are intended to encompass non-exclusive inclusion such that a circuit structure, article or device comprising a list of elements includes not only those elements, but also other elements not expressly listed , or an element inherent to the article or device. Without further limitation, the phrase "comprising a..." defines an element that does not preclude the presence of additional identical elements in the article or device comprising said element. Relational terms such as the terms "first" and "second" are used only to distinguish one entity or operation from another and do not necessarily require or imply that any such entity or operation exists between them. The actual relationship or sequence.

It should be understood that the present invention is not limited to the precise structures described above and illustrated in the accompanying drawings, and that various modifications and changes may be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims (4)

1. A distribution line fault positioning method based on pulse signal injection is characterized by comprising the following steps:

a plurality of partial discharge detection sensors sequentially installed on a distribution line monitor first pulse signals sent out at fault points;

analyzing and obtaining the relative phase of the first pulse signal monitored by all the partial discharge detection sensors relative to a power frequency voltage signal on the distribution line;

obtaining a first monitoring position where the corresponding partial discharge detection sensor is located when the relative phase is the minimum value, and a second monitoring position and a third monitoring position which are adjacent to the first monitoring position;

acquiring a first relative phase, a second relative phase and a third relative phase of the first pulse signal corresponding to the first monitoring position, the second monitoring position and the third monitoring position;

analyzing the first relative phase, the second relative phase and the third relative phase, and calculating to obtain a first distance between the first monitoring position and the second monitoring position and a second distance between the first monitoring position and the third monitoring position;

judging the section where the fault point is located according to the first distance and the second distance;

if the first distance is equal to the length of the section between the first monitoring location and the second monitoring location stored by the system and the second distance is not equal to the length of the section between the first monitoring location and the third monitoring location stored by the system, the fault is located between the first monitoring location and the third monitoring location;

if the first distance is not equal to a system stored length value of a segment between the first monitoring location and the second distance is equal to a system stored length value of a segment between the first monitoring location and the third monitoring location, then the fault is located between the first monitoring location and the second monitoring location;

the length of the section between the first monitoring position and the second monitoring position stored by the system and the length of the section between the first monitoring position and the third monitoring position stored by the system are derived from data obtained and stored by online ranging of the distribution line, and the online ranging comprises the following steps:

selecting a monitoring position of any one partial discharge detection sensor on a distribution line, and injecting a second pulse signal into the monitoring position;

all the partial discharge detection sensors monitor and obtain the second pulse signals;

analyzing all the second pulse signals to obtain the relative phases of the second pulse signals at all the monitoring positions relative to the power frequency voltage signals;

calculating a relative phase difference of the second pulse signal from one of the monitoring positions to an adjacent one of the monitoring positions;

according to the relative phase difference, the distance between the monitoring position and the adjacent monitoring position is obtained and stored, and the distance is as follows:

wherein V is the propagation speed of the pulse signal in the distribution line, and V is 3 x 10 ⁸ m/s (speed of light).

2. The method according to claim 1, wherein the phase of the maximum amplitude intensity of the first pulse signal is the fault phase.

3. The method according to claim 1, wherein the first distance is:

wherein, V is the propagation speed of the pulse signal in the line, and V is 3 × 10 ⁸ m/s (speed of light).

4. The method according to claim 1, wherein the second distance is:

wherein, V is the propagation speed of the pulse signal in the line, and V is 3 × 10 ⁸ m/s (speed of light).

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